Sink stopper



FIG. 1 is a perspective view of the sink stopper showing my new design;

FIG. 2 is an elevation view of the sink stopper;

FIG. 3 is a top plan view of the sink stopper; and,

FIG. 4 is a bottom plan view of the sink stopper.

The broken line showing of structural lines is included for the purpose of illustrating non-claimed subject matter and forms no part of the claimed design. 

CLAIM The ornamental design for a sink stopper, as shown and described. 